1. Field of the Invention
The present invention relates to a motorcycle in which a rear wheel is rotatably supported by a pair of rear arms. In particular, the present invention concerns a rear wheel suspension structure for suspending a rear wheel.
2. Description of the Relevant Art
Japanese Patent Laid-open No. 301563/1999 discloses a motorcycle in which a rear wheel is rotatably supported by a pair of rear arms. The rear arms are vertically swingably supported by an engine body. In this known motorcycle, both rear arms are constructed as a unitary member from their front portions, supported by the engine body, to their rear portions, which support the rear wheel.
This known rear suspension system for the rear wheel of a motorcycle has drawbacks. When service work is to be performed, such as the replacement of a rear wheel tire, an axle inserted through the rear wheel must be extracted or pulled out, before the rear wheel is removed. Therefore, when the rear wheel is to be reinstalled, it is necessary to establish and hold a raise position of the rear wheel between both rear arms. While holding the rear wheel between the two rear arms, the is axle inserted through one of the rear arms, then the rear wheel, and then the other rear arm to mount the rear wheel. Holding and properly aligning the rear wheel is difficult and therefore servicing performance is poor.
It is possible to avoid removing the axle by removing the whole of the second rear arm. The second rear arm is vertically pivotably supported by the engine body. Therefore, in this case it is necessary to take some measure for preventing the adhesion of dust to a bearing portion of the second rear arm. Therefore, removal of the whole of the second rear arm should be avoided in servicing the rear wheel.
It is an object of the present invention to address one or more of the drawbacks associated with the background art.
It is an object of the invention is to provide a rear wheel suspension structure, for a vehicle, such as a motorcycle, which is capable of improving the rear wheel servicing performance while eliminating the need of considering a measure against the adhesion of dust to the bearing portion of the second rear arm when servicing the rear wheel.
These and other objects are accomplished by a motorcycle in which an engine body of an engine is mounted on a body frame non-swingably and a rear wheel is disposed between and supported rotatably by a first rear arm and a second rear arm. The first rear arm is vertically swingably supported by the engine body and forms a part of a case which incorporates a power train system for transmitting power from the engine to the rear wheel. The second rear arm is vertically swingably supported by the engine body about an axis which is coaxial with a swing axis of the first rear arm. The second rear arm includes a plurality of arm members, including a front arm member supported swingably by the engine body and a rear arm member which supports the axle of the rear wheel rotatably. The plural arm members are connected together so that they can be disconnected from each other.
With this configuration, by separating the rear arm member out of the components of the second rear arm, the rear wheel can be removed sideways on the side opposite to the first rear arm without pulling out the axle. Also, at the time of mounting of the rear wheel all that is required is merely passing the axle as supported on the first rear arm side through the rear wheel and mounting the rear arm member. Therefore, the rear wheel servicing performance can be improved in comparison with the conventional structure in which the axle is passed through the rear wheel which must be raised and held in an established position.
Further, in the present invention, the portion of the second rear arm where the second rear arm is supported by the engine body is not disassembled in servicing the rear wheel. Therefore, there is no fear of dust adhesion to the bearing portion of the second rear arm. Thus, it is not necessary to consider taking any measure against the adhesion of dust.
According to the present invention, there is provided a rear wheel suspension structure wherein the front arm member is connected separably to the first rear arm between the engine body and the rear wheel. The rear arm member is connected separably to the front arm member while maintaining the connected state of the front arm member to the first rear arm. With this configuration, the rear wheel can be removed outwardly sideways without disassembling the connection between the first and second rear arms, thus preventing the occurrence of twist relative to both rear arms which are connected together between the engine body and the rear wheel. Therefore, the rear wheel servicing performance can be further improved.
According to the present invention, there is provided a rear wheel suspension structure wherein the axle of the rear wheel and a final output shaft of the power train system are contiguous to each other coaxially and integrally. With this configuration, the final output shaft of the power train system also serves as the rear wheel axle. Therefore, the construction of the power train system can be simplified.
Further, according to the present invention, there is provided a rear wheel suspension structure wherein in the rear arm, the front arm member is connected separably to the rear arm member which is capable of being connected separably to the first rear arm between the engine body and the rear wheel. With this configuration, by subassembling the rear arm member in the second rear arm, the first rear arm connected to the rear arm member, and the rear wheel supported through the axle by the rear arm member and the first rear arm, and by mounting the first rear arm to the engine body, mounting the front arm member which constitutes a part of the second rear arm and connecting it to the rear arm member, both rear arms which support the rear wheel through the axle can be installed to the engine body. Therefore, the rear wheel installing performance can be improved.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.